232 research outputs found

    The Effect of Different Photoperiods in Circadian Rhythms of Per3

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    The aim of this study was to analyse the circadian behavioural responses of mice carrying a functional knockout of the Per3 gene (Per3(-/-)) to different light : dark (L : D) cycles. Male adult wild- type (WT) and Per3(-/-) mice were kept under 12- hour light : 12hour dark conditions (12L : 12D) and then transferred to either a short or long photoperiod and subsequently released into total darkness. All micewere exposed to both conditions, and behavioural activity datawere acquired through runningwheel activity and analysed for circadian characteristics during these conditions. We observed that, during the transition from 12L : 12D to 16L : 8D, Per3(-/-)mice take approximately one additional day to synchronise to the new L : D cycle compared toWT mice. Under these long photoperiod conditions, Per3(-/-) mice were more active in the light phase. Our results suggest that Per3(-/-) mice are less sensitive to light. the data presented here provides further evidence that Per3 is involved in the suppression of behavioural activity in direct response to light.Biotechnology and Biological Sciences Research Council (BBSRC)Royal Society (Malcolm von Schantz)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Universidade Federal de São Paulo UNIFESP, Dept Psicobiol, BR-04024002 São Paulo, BrazilUniv Surrey, Fac Hlth & Med Sci, Guildford GU2 5XH, Surrey, EnglandUniv Fed Rio Grande do Norte, UFRN, Dept Fisiol, BR-59072970 Natal, RN, BrazilInst Fed Sudeste Minas Gerais, Barbacena, MG, BrazilUniv São Paulo, Escola Artes Ciencias & Humanidades, São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Psicobiol, BR-04024002 São Paulo, BrazilBiotechnology and Biological Sciences Research Council (BBSRC): BB/E003672/1FAPESP: 2007/05037-9FAPESP: CEPID 98/14303-3Web of Scienc

    Breast Cancer Detection by Preoperative Imaging in Reduction Mammaplasty Patients : A Single Center Study of 918 Patients

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    Background The role of preoperative imaging and the usability of different imaging modalities is highly variable and controversial in reduction mammaplasty patients. Our study describes the imaging process in a single center in regard to modality selection, age and timing, and of the association between imaging and histopathological findings in reduction mammaplasty specimens. Methods Nine hundred eighteen women, who underwent reduction mammaplasty during 1.1.2007-31.12.2011, were retrospectively reviewed for demographics, preoperative imaging, further preoperative examinations, and pathology reports. Results Preoperative imaging had been conducted for 89.2% (n = 819) of the patients. In 49 (6.0%) patients, suspicious preoperative imaging led to further examinations revealing 2 high-risk lesions (atypical ductal hyperplasia (ADH), lobular carcinoma in situ (LCIS)), and 2 cancers preoperatively. Postoperatively abnormal histopathology specimens were revealed in 88 (10.4%) patients. The incidence of high-risk lesions was 5.5% (n = 47), and the incidence of cancer was 1.2% (n = 10). Preoperative imaging was normal (BI-RADS 1 and BI-RADS 2) in 80.8% of these patients. The sensitivity of the preoperative imaging for cancer detection was 20.0%, and the specificity was 100.0%. Conclusions Preoperative imaging and further examinations do not sufficiently detect malignant or cancer risk-increasing findings. Therefore, histopathological analysis of reduction mammaplasty specimens seems mandatory.Peer reviewe

    Should we routinely analyze reduction mammaplasty specimens?

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    Background: Reduction mammaplasty is one of the most common plastic surgery procedures. Preoperative imaging and histopathology protocols vary among countries and institutions. We aimed to analyze the incidence of occult breast cancer and high-risk lesions in reduction mammaplasty specimens. We also analyzed whether patients with abnormal histopathology differed from the study population in terms of demographics. Patients and methods: In total, 918 women who underwent reduction mammaplasty from January 2007 to December 2011 were retrospectively reviewed for demographics, preoperative imaging, further preoperative examinations, pathology reports, and postoperative follow-up. Results: Abnormal histopathological findings were revealed in 88 (10%) patients with a mean age of 49.5 +/- 10.2 years. The incidence of breast cancer was 1.2%, and the incidence of high-risk lesions (atypical ductal and lobular hyperplasia and lobular carcinoma in situ) was 5.5%. Age and specimen weights were significantly higher in patients with abnormal histopathology. Eighty-one percent of patients with abnormal histopathology had normal preoperative imaging revealing two high-risk and two cancer findings. Two patients developed breast cancer in the same breast in which the high-risk lesion was originally detected. Conclusion: Women with abnormal histopathology cannot be sufficiently detected preoperatively. Therefore, histopathological analysis of reduction mammaplasty specimens seems mandatory. Reduction mammaplasty combined with subsequent histopathological examination offers a sufficient chance of detecting cancer and risk-increasing lesions that merits the cost of histopathology. (C) 2016 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.Peer reviewe

    The Effect of Different Photoperiods in Circadian Rhythms of Per3 Knockout Mice

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    The aim of this study was to analyse the circadian behavioural responses of mice carrying a functional knockout of the Per3 gene (P e r 3 - / -) to different light: dark (L: D) cycles. Male adult wild-type (WT) and P e r 3 - / - mice were kept under 12-hour light: 12-hour dark conditions (12L: 12D) and then transferred to either a short or long photoperiod and subsequently released into total darkness. All mice were exposed to both conditions, and behavioural activity data were acquired through running wheel activity and analysed for circadian characteristics during these conditions. We observed that, during the transition from 12L: 12D to 16L: 8D, P e r 3 - / - mice take approximately one additional day to synchronise to the new L: D cycle compared to WT mice. Under these long photoperiod conditions, P e r 3 - / - mice were more active in the light phase. Our results suggest that P e r 3 - / - mice are less sensitive to light. The data presented here provides further evidence that Per3 is involved in the suppression of behavioural activity in direct response to light

    Using the MitoB method to assess levels of reactive oxygen species in ecological studies of oxidative stress

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    In recent years evolutionary ecologists have become increasingly interested in the effects of reactive oxygen species (ROS) on the life-histories of animals. ROS levels have mostly been inferred indirectly due to the limitations of estimating ROS from in vitro methods. However, measuring ROS (hydrogen peroxide, H2O2) content in vivo is now possible using the MitoB probe. Here, we extend and refine the MitoB method to make it suitable for ecological studies of oxidative stress using the brown trout Salmo trutta as model. The MitoB method allows an evaluation of H2O2 levels in living organisms over a timescale from hours to days. The method is flexible with regard to the duration of exposure and initial concentration of the MitoB probe, and there is no transfer of the MitoB probe between fish. H2O2 levels were consistent across subsamples of the same liver but differed between muscle subsamples and between tissues of the same animal. The MitoB method provides a convenient method for measuring ROS levels in living animals over a significant period of time. Given its wide range of possible applications, it opens the opportunity to study the role of ROS in mediating life history trade-offs in ecological settings

    Casein Kinase 1 Underlies Temperature Compensation of Circadian Rhythms in Human Red Blood Cells

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    Temperature compensation and period determination by casein kinase 1 (CK1) are conserved features of eukaryotic circadian rhythms, whereas the clock gene transcription factors that facilitate daily gene expression rhythms differ between phylogenetic kingdoms. Human red blood cells (RBCs) exhibit temperature-compensated circadian rhythms, which, because RBCs lack nuclei, must occur in the absence of a circadian transcription-translation feedback loop. We tested whether period determination and temperature compensation are dependent on CKs in RBCs. As with nucleated cell types, broad-spectrum kinase inhibition with staurosporine lengthened the period of the RBC clock at 37°C, with more specific inhibition of CK1 and CK2 also eliciting robust changes in circadian period. Strikingly, inhibition of CK1 abolished temperature compensation and increased the Q10 for the period of oscillation in RBCs, similar to observations in nucleated cells. This indicates that CK1 activity is essential for circadian rhythms irrespective of the presence or absence of clock gene expression cycles

    Compared Heritability of Chronotype Instruments in a Single Population Sample

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    It is well established that the oldest chronotype questionnaire, the morningness-eveningness questionnaire (MEQ), has significant heritability, and several associations have been reported between MEQ score and polymorphisms in candidate clock genes, a number of them reproducibly across populations. By contrast, there are no reports of heritability and genetic associations for the Munich chronotype questionnaire (MCTQ). Recent genome-wide association studies (GWAS) from large cohorts have reported multiple associations with chronotype as assessed by a single self-evaluation question. We have taken advantage of the availability of data from all these instruments from a single sample of 597 participants from the Brazilian Baependi Heart Study. The family-based design of the cohort allowed us to calculate the heritability (h2) for these measures. Heritability values for the best-fitted models were 0.37 for MEQ, 0.32 for MCTQ, and 0.28 for single-question chronotype (MEQ Question 19). We also calculated the heritability for the two major factors recently derived from MEQ, “Dissipation of sleep pressure” (0.32) and “Build-up of sleep pressure” (0.28). This first heritability comparison of the major chronotype instruments in current use provides the first quantification of the genetic component of MCTQ score, supporting its future use in genetic analysis. Our findings also suggest that the single chronotype question that has been used for large GWAS analyses captures a larger proportion of the dimensions of chronotype than previously thought
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